Editor Charles H. Smith's Note: This paper, read
at the Royal Geographical Society meeting of 8 June 1863 (and
published in volume 33 of their Journal series later the same year),
was a notable success, and did much to solidify Wallace's reputation as the leading
expert on the natural history of the Indonesia region. Discussion following the
paper's presentation was recorded, separately, in volume seven (for 1862-63),
issue five, of the Society's Proceedings series. Both are reproduced below, with
the original paginations indicated within double brackets. To link directly to
this page, connect with: http://people.wku.edu/charles.smith/wallace/S078.htm

[[p. 217]] The Malay
or Indian Archipelago is that extensive group of islands which occupies
the space between south-eastern Asia and Australia, and divides the
Indian from the Pacific Ocean. From whatever point of view we survey
this portion of the earth's surface--whether as regards its superficial
extent, or the immense number of islands with which it is overspread,
or the individual size of those islands; whether we examine their peculiarities
of climate, or their geological structure, their rich and varied vegetation,
their wonderful animal productions, or the strongly-contrasted races
of mankind that inhabit them; or if, lastly, we look at them from a
commercial and political point of view, noting the varied products
which
they furnish to supply the necessities and luxuries of mankind, trace
the struggles of the chief nations of Europe for a share in their fertile
soil, and watch the interesting moral and political problems now being
worked out there; we shall be convinced that no part of the world can
offer a greater number of interesting facts for our contemplation,
or
furnish us with more extensive and varied materials for speculation
in almost every great department of human knowledge.

On the present occasion I propose to give a sketch
of what is most interesting in the physical geography of this region,
including [[p. 218]] in that term the general
relations of the organic world to the present and past conditions of
the earth's surface.

1. Definition of the Archipelago, Position, Extent,
and Magnitude of the chief Islands.--It first becomes necessary
to define accurately the limits of the Archipelago, pointing out exactly
what islands we include within it; for, though "all the islands between
south-eastern Asia and Australia" seems pretty definite, yet to the
eastward this region blends insensibly into the vast extent of the Pacific
islands. According to my views, the Malay--or, as I should prefer to
name it, the Indo-Australian--Archipelago extends from the Nicobar
Islands on the north-west to St. Christoval, one of the Solomon
Islands, on the south-east, and from Luzon on the north to Rotti,
near Timor, on the south. The eastern boundary is drawn at this particular
point for reasons which will be explained further on. Though not geographically
correct to include any part of a continent in an archipelago, it is
necessary for our purpose to consider the Malay peninsula as not only
almost but quite an island, since it cannot be physically separated
from the region of which we are now treating.

Thus limited, the Archipelago is of a somewhat triangular
form, with an extreme length of about 5000, and a breadth of rather
more than 2000 English miles. The mere statement of these dimensions,
however, will give but an imperfect idea of the extent and geographical
importance of this region, which, owing to its peculiar position, is
worse represented on maps than any other on the globe. In many atlases
of great pretension there is no map of the whole Archipelago. A small
portion of it generally comes in with Asia, and another piece with the
Pacific Islands; but in order to ascertain its form and extent as a
whole we are almost always obliged to turn to the map of the Eastern
Hemisphere. It thus happens that seldom seeing this region, except on
a diminutive scale, its real form, dimensions, and the size, situations,
and names of its component islands, are, perhaps, less familiar to educated
persons than those of any other countries of equal importance. They
can hardly bring themselves to imagine that this sea of islands is really
in many respects comparable with the great continents of the earth.
The traveller, however, soon acquires different ideas. He finds himself
sailing for days or even for weeks along the shores of one of these
great islands, often so great that the inhabitants believe it to be
a boundless continent. He finds that voyages among these islands are
commonly reckoned by weeks and months, and that the inhabitants of the
eastern and western portions of the Archipelago are as mutually unknown
to each other as are the native races of North and South America. On
visiting the coasts of one of the larger islands, he hears of the [[p.
219]] distinct kingdoms which lie along its shores, of the remote
north or east or south of which he can obtain little definite information,
and of the wild and inaccessible interior, inhabited by cannibals and
demons, the haunt of the charmed deer which bears a precious jewel in
its forehead, and of the primæval men who have not yet lost their
tails. The traveller, therefore, soon looks upon this region as one
altogether apart. He finds it possesses its own races of men and its
own aspects of Nature. It is an island-world, with insular ideas and
feelings, customs, and modes of speech; altogether cut off from the
great continents into which we are accustomed to divide the globe, and
quite incapable of being classed with any of them. Its dimensions, too,
are continental. You may travel as many thousand miles across it, in
various directions, occupying as many weeks and months as would be necessary
to explore any of the so-called quarters of the globe. It contains as
much variety in its climate, in its physical phenomena, its animate
and inanimate life, and its races of mankind as some of those regions
exhibit. If, therefore, the claim of Australia to be a fifth
division of the globe be admitted, I would ask for this great archipelago
(at least on the present occasion) to be considered a sixth.

I will now endeavour to give you a clearer idea
of its extent and magnitude by comparing it with some regions nearer
home. If, first, we bring the Malay Archipelago to Europe, keeping the
meridians parallel, and place the western extremity of the island of
Sumatra upon the Land's End, New Guinea will then spread
over Turkey and a good deal of Persia, and the Solomon
Islands will reach to the borders of the Punjaub; while the
northern extremity of Luzon will be near the White Sea,
and the islands of Timor and Rotti in Syria. The
area of the whole Archipelago is, however, much less than its dimensions
would seem to imply, being, on a fair calculation, about equal to that
portion of Europe which lies south of St. Petersburg and the Shetland
Islands.

Again, if we compare it with Equatorial America,
we shall find its extent in longitude to exceed the width of that great
continent, Sumatra stretching out into the Pacific to the west
of Panama, while New Guinea would be washed by the
Atlantic
to the east of Pernambuco.

This great region of mingled land and water is,
then, as a whole, comparable in its dimensions with the primary divisions
of the earth, while its component parts are on an equally extended scale,--two
of the islands, Borneo and New Guinea, being the largest
on the globe. They are nearly equal in extent, and the only other island
which approaches them is Madagascar. Borneo would contain within
its vast area the whole of Great Britain and [[p.
220]] Ireland, with all their islets from Scilly to Shetland
in their true relative positions, and still leave boundless forests
stretching out like an ocean beyond them. Then comes Sumatra,
about equal to Great Britain; after which follow Java, Luzon,
and Celebes, either of which may compare in size with Ireland
or one of the larger New Zealand Islands. After these succeed
eighteen islands, which average as large as Jamaica; more than one
hundred about the size of the isles of Wight and Man, with many
thousands of isles and islets below these, and which are practically
innumerable.

In their physical constitution and attendant phenomena
the islands of the Archipelago offer us some remarkable and instructive
contrasts. Active and extinct volcanoes are abundant in many of the
islands, in others they are altogether absent. The former, as a general
rule, are subject to frequent earthquakes, which in the others are quite
unknown. In the greater part of the Archipelago one vast, ever-verdant
forest covers hill and valley, plain and mountain, up to the very loftiest
summits; whereas in another and much smaller portion such dense and
gloomy forests are altogether unknown, the country consisting of arid
hills and plains, with a comparatively scanty covering of shrubs and
trees. Again, over some extensive districts the monsoons, or periodical
winds, with their attendant rains or drought, divide the year into a
well-defined and regularly-recurring wet and dry season. Over other
scarcely less extensive districts no such regularity exists; the inhabitants
themselves can hardly tell you when their rainy or dry season usually
begins, and the traveller soon finds the climate to be almost as variable
and the skies as inconstant as in our own much-abused island. Even in
districts where the season is regular, there are no less striking contrasts;
one portion of an island having its wet weather while the remainder
is parched up, and islands within sight of each other having very different
seasons.

There is yet another contrasting aspect in which
the Archipelago may be viewed, less obvious but leading to far more
important results than any I have yet mentioned, namely, that one large
portion of it is connected by a very shallow sea to the continent of
Asia, another part is similarly joined to Australia, while the remaining
islands are surrounded by a practically unfathomable ocean. We shall
consider the chief islands of the Archipelago, therefore, under the
heads of,--1st. Volcanic and Non-Volcanic; 2nd. Forest
Country and Open Country; 3rd. Well-marked Seasons
and Undefined Seasons; and 4th. The Western or Indo-Malayan
Region, and the Eastern or Austro-Malayan Region.

Looking at a map on which the volcanic regions of
the Archipelago are marked out--those which are subject to earthquakes,
which are of volcanic origin, and which abound more or less in [[p.
221]] extinct as well as active volcanoes--we see at a glance
that the great islands of Borneo and Celebes form the central mass around
which the volcanic islands are distributed so as rudely to follow their
outline and embrace them on every side but one in a vast fiery girdle.
Along this great volcanic band (about 5000 miles in length) at least
fifty mountains are continually active, visibly emitting smoke or vapour;
a much larger number are known to have been in eruption during the last
300 years; while the number which are so decidedly of volcanic origin
that they may at any moment burst forth again, must be reckoned by hundreds.

In the whole region occupied by this volcanic belt,
and for a considerable breadth on each side of it, earthquakes are of
continual recurrence, slight shocks being felt at intervals of every
few weeks or months, while more severe ones, shaking down whole villages,
and doing more or less injury to life and property, are sure to happen
in one part or another of this district almost every year. In many of
the islands the years of the great earthquakes form the chronological
epochs of the native inhabitants, by the aid of which the ages of their
children are remembered, and the dates of many important events are
determined.

It is not now my object to describe the many fearful
eruptions that have taken place in this region. In the amount of injury
to life and property, and in the magnitude of their effects, they have
not been surpassed by any upon record. Forty villages were destroyed
by the eruption of Papaudayang in Java, where the whole mountain was
blown up by repeated explosions, and a large lake left in its place.
By the great eruption of Toruboro in Sumbawa 12,000 people were destroyed,
and the ashes darkened the air, and fell thick upon the earth and sea
for 300 miles round. Even quite recently, since I quitted the country,
a mountain which had been quiescent for more than 200 years suddenly
burst into activity. The island of Makiau, one of the Moluccas, was
rent open in 1646 by a violent eruption which left a huge chasm on one
side, extending into the heart of the mountain. It was, when I last
visited it, clothed with vegetation to the summit, and contained twelve
populous Malay villages. On the 29th of December, 1862, after 215 years
of perfect inaction, it again suddenly burst forth, blowing up and completely
altering the appearance of the mountain, destroying the greater part
of the inhabitants, and sending forth such volumes of ashes as to darken
the air at Ternate, 40 miles off, and almost entirely to destroy the
growing crops on that and the surrounding islands.

The island of Java contains more volcanoes, active
and extinct, than any other known district of equal extent. They are
about forty-five in number, and many of them exhibit most beautiful
examples of the volcanic cone on a large scale, single or double, [[p.
222]] with entire or truncated summits, and averaging 10,000
feet high.

It is now well ascertained that almost all volcanoes
have been slowly built up by the accumulation of the matter--mud, ashes,
and lava--ejected by themselves. The openings or craters, however, frequently
shift their position; so that a country may be covered with a more or
less irregular series of hills in chains and masses only here and there
rising into lofty cones, and yet the whole may be produced by true volcanic
action. In this manner the greater part of Java has been formed. There
has been some elevation, especially on the south coast, where are extensive
cliffs of raised coral limestone; and there may be a substratum of older
stratified rocks, but still essentially Java is volcanic; and that noble
and fertile island--the very garden of the East, and perhaps upon the
whole the richest, the best cultivated, and the best governed tropical
island in the world--owes its very existence to the same intense volcanic
activity which still occasionally devastates its surface.

The great island of Sumatra exhibits in proportion
to its extent a much smaller number of volcanoes, and a considerable
portion of it has had probably a non-volcanic origin.

To the eastward the long string of islands from
Java passing by the north of Timor and away to Banda are probably all
due to volcanic action. Timor itself consists of ancient stratified
rocks, but is said to have one volcano near its centre.

Going northward, Amboyna, a part of Bouru, and the
west end of Ceram, the north part of Gilolo and all the small islands
around it, the northern extremity of Celebes, and the islands of Siau
and Sauguir are wholly volcanic. The Philippine Archipelago contains
many active and extinct volcanoes, and has probably been reduced to
its present fragmentary condition by subsidences attending on volcanic
action.

All along this great line of volcanoes are to be
found more of less palpable signs of great upheaval and depression of
land. The range of islands south of Sumatra, a part of the south coast
of Java, and of the islands east of it, the west and east end of Timor,
portions of all the Moluccas, the Ké and Aru Islands, Waigiou,
and the whole south and east of Gilolo consist in a great measure of
upraised coral-rock, exactly corresponding to that now forming in the
adjacent seas. In many places I have observed the very surfaces of the
upraised reefs, with the great masses of coral standing up in their
natural position and hundreds of shells, so fresh-looking that it was
hard to believe they had been more than a few years out of the water;
and, in fact, it is very probable that such changes have occurred within
a few centuries.

In striking contrast with this region of subterranean
fires, the [[p. 223]] island of Celebes
in all its southern peninsulas, the great mass of Borneo, and the Malay
peninsula, are not known to contain a single volcano, active or extinct.
To the east of the volcanic band is another quiescent area of 1000 miles
wide, the great island of New Guinea being free from volcanoes and earthquakes.
Towards its eastern extremity, however, these reappear in some small
islands off its coast, and in New Britain, New Ireland, and the Solomon
Islands, which contain active volcanoes.

The difference between the aspect of the volcanic
and the non-volcanic regions is by no means so striking as might be
imagined. Where active volcanoes or true volcanic peaks exist, a peculiar
character is at once given to the islands, which are also in almost
every case characterised by excessive fertility. In many of the adjoining
districts, however, though volcanic products may be everywhere visible,
the general aspect of the country, the outline of the hills, and the
character of the vegetation, does not differ materially from those of
many parts of Borneo and New Guinea. The island of Amboyna, for instance,
consists principally of raised coral-rock almost everywhere covered
with deep-red volcanic clays and gravels, and in places capped with
basalt and lavas; yet the soil is by no means fertile, and where the
native forest vegetation is cleared off, the ground bears only a scanty
covering of dwarf shrubs and rigid herbage. The chief characteristic
of the non-volcanic regions appears to me to consist in the great flat
valleys that line the coasts, and penetrate far inland between the mountain
ranges--the result of the long and uninterrupted action of rivers and
tropical rains (combined probably with a slow elevation of the land)
in filling up the gulfs that once intervened between the mountain ranges.
A subsidence of a few hundred feet would reduce Borneo into a shape
very similar to that of Celebes, which island may be considered to be
now in the state that Borneo has just passed out of, and to be still
engaged in filling up and converting into swampy plains the deep gulfs
that at present occupy the spaces between her radiating lines of mountains.

The very extraordinary forms of Celebes and Gilolo
have been imputed by some authors to sudden and capricious elevation.
Mr. Windsor Earl speaks of the volcanic action where it was strongest
"throwing the islands into fantastic forms." Celebes, however, is free
from volcanoes except at its northern extremity, and its southern peninsula
consists of mountains of basalt and limestone. From peculiarities in
its natural productions, the shallowness of some of the gulfs between
its peninsulas, and the number of coral islets that surround the southern
portion of it, Celebes was once probably much more extensive, perhaps
equal to Borneo, at a time when Borneo was just rising above the ocean,
[[p. 224]] and having the form rudely represented
in the diagram. As in every part of the world of which we have accurate
geological knowledge, risings and sinkings of the land to the amount
of several hundreds of feet have repeatedly occurred, these two islands
may each have successively assumed the form of the other without any
violent convulsion. From the vast, swampy, level plains which stretch
into the very heart of Borneo, allowing vessels to ascend its southern
rivers about 300 miles in a straight line, it has probably been for
a long time stationary, and thus been enabled to fill up the gulfs that
formerly penetrated it. At a still earlier period it must have been
much more deeply submerged, when the extensive coal-beds found in almost
every part of it were being formed. This, however, was at no very remote
period, geologically speaking, for the coal of Borneo is all tertiary.
Instead of the ferns and lepidodendra, and other plants of extinct genera
which abound in our coal-shales, those of Borneo contain only impressions
of leaves of exogenous trees which can hardly be distinguished from
those growing in the surrounding forests.

The contrasts of vegetation and of climate in the
Archipelago may best be considered together, the one being to some extent
dependent on the other.

Placed immediately upon the Equator, and surrounded
by extensive oceans, it is not surprising that the various islands of
the Archipelago should be almost always clothed with a forest vegetation
from the level of the sea to the summits of the loftiest mountains.
This is the general rule. Sumatra, New Guinea, Borneo, the Philippines
and the Moluccas, and the uncultivated parts of Java and Celebes, are
all forest countries, except a few small and unimportant tracts, due
perhaps, in some cases, to ancient cultivation or accidental fires.
To this, however, there is one important exception in the island of
Timor and all the smaller islands opposite, in which there is absolutely
no forest such as exists in the other islands, and this character extends
in a lesser degree to Flores, Sumbawa, Lombock, and Bali.

In Timor the most common trees are Eucalypti
of several species, so characteristic of Australia, with sandalwood,
acacia, and other sorts in less abundance. These are scattered over
the country more or less thickly, but never so as to deserve the name
of a forest. Coarse and scanty grasses grow beneath them on the more
barren hills, and a luxuriant herbage in the moister localities. In
the islands between Timor and Java there is often a more thickly wooded
country, but thorny and prickly trees abound. They seldom reach any
great height, and during the force of the dry season they almost completely
lose their leaves, allowing the ground to be parched beneath them, and
contrasting strongly with [[p. 225]] the
damp, gloomy, ever-verdant forests of the other islands. This peculiar
character, which extends in a less degree to the southern peninsula
of Celebes and the east end of Java, is most probably owing to the proximity
of Australia. The south-east monsoon, which lasts for about two-thirds
of the year (from March to November), blowing over the northern parts
of that country, produces a degree of heat and dryness which assimilates
the vegetation and physical aspect of the adjacent islands to its own.
A little further eastward in Timorlaut and the Ké Islands, a
moister climate prevails, the south-east winds blowing from the Pacific
through Torres Straits, and as a consequence every rocky islet is clothed
with verdure to its very summit. Further west again, as the same winds
blow over a wider and wider extent of ocean, they have time to absorb
fresh moisture, and we accordingly find the island of Java possessing
a less and less arid climate in the dry season, till in the extreme
west near Batavia rain occurs more or less all the year round, and the
mountains are everywhere clothed with forests of unexampled luxuriance.

The changes of the monsoons and of the wet and dry
seasons in some parts of the Archipelago, are very puzzling; and an
accurate series of observations in numerous localities is required to
elucidate them.

"Speaking generally," said Mr. Wallace, "the whole
south-western part
of the Archipelago, including the whole range of islands from Sumatra
to Timor, with the larger half of Borneo and the southern peninsula
of Celebes, have a dry season from April to November, with the south-east
monsoon. This same wind, however, bends round Borneo, becoming the
south-west
monsoon in the China sea, and bringing the rainy season to Northern
Borneo and the Philippines."

In the Moluccas and New Guinea the seasons are most
uncertain. In the south-east monsoon from April to November, it is often
stormy at sea, while on the islands it is very fine weather. There is
generally not more than two or three months of dry hot weather about
August and September. This is the case in the northern extremity of
Celebes and in Bouru, whereas in Amboyna July and August are the worst
months in the year. In Ternate, where I resided at intervals for three
years, I never could find out which was the wet and which the dry season.
The same is the case at Banda, and a similar uncertainty prevails in
Menado, showing probably that the proximity of active volcanoes has
a great disturbing meteorological influence. In New Guinea a great amount
of rain falls more or less all the year round. On the whole the only
general statement we can make seems to be that the countries within
about 3° on each side of the Equator have much rain and not very
strongly contrasted seasons; while those with more south [[p.
226]] or north latitude, have daily rains during about four months
in the year, while for five or six months there is almost always a cloudless
sky and a continual drought.

We have next to consider the Malayan Archipelago
in its geological and zoological relations to Asia and to Australia,
it being now a well established fact that one portion of it is almost
as much Asiatic in its organic productions as the British Isles are
European, while the remainder bears the same relation to Australia that
the West India Islands do to America.

It was first pointed out by Mr. George Windsor Earl,
in a paper read before this Society eighteen years ago, that a shallow
sea connected the great islands of Sumatra, Borneo, and Java, to the
Asiatic continent, with which they generally agreed in their natural
productions; while a similar shallow sea connected New Guinea and some
of the adjacent islands to Australia. Owing, however, to that gentleman's
imperfect knowledge of the natural history of the various islands, he
did not fully appreciate the important results of this observation,
and in fact in the same paper argued in favour of the former connection
of Asia and Australia--a connection to which the whole bearing of the
facts in physical geography and natural history is plainly opposed.

In order to make this subject intelligible, it is
necessary to make a few observations on the relations of the geographical
distribution of animals and plants with geology.

It is now generally admitted that the present distribution
of living things on the surface of the earth, is mainly the result of
the last series of changes that the surface has undergone. Geology teaches
us that the surface of the land and the distribution of land and water
is everywhere slowly changing. It further teaches us that the forms
of life which inhabit that surface have, during every period of which
we possess any record, been also slowly changing.

It is not now necessary to say anything about how
either of those changes took place; as to that, opinions may differ;
but as to the fact that the changes themselves have occurred
from the earliest geological ages down to the present day, and are still
going on, there is no difference of opinion. Every successive stratum
of sedimentary rock, sand or gravel, is a proof that changes of level
have taken place; and the different species of animals and plants, whose
remains are found in these deposits, prove that corresponding changes
did occur in the organic world.

Taking, therefore, these two series of changes for
granted, some of their effects are visible in the present peculiarities
and anomalies in the distribution of species. In our own islands, with
a few very trifling exceptions, every quadruped, bird, reptile, insect,
and plant, is found also on the adjacent continent. In the small island
of Corsica, there are some quadrupeds, birds and insects quite peculiar
[[p. 227]] to it; in Ceylon, more closely
connected to India than Britain is to Europe, many animals and plants
of all kinds are quite different from those found in India. In the Galapagos
Islands every indigenous living thing is peculiar to them, though closely
resembling other kinds found in the neighbouring parts of the American
continent.

Now, in all cases where we have independent geological
evidence, we find that those islands, the productions of which are identical
with those of the adjacent countries, have been joined to them within
a comparatively recent period, such recent unity being in most cases
indicated by the very shallow sea still dividing them; while in cases
where the natural productions of two adjacent countries is very different,
they have been separated at a more remote epoch--a fact generally indicated
by a deeper sea now dividing them. The reason of this is obvious. For
example: let a subsidence take place, cutting off any portion of a continent,
and forming an island. The organic productions of the two portions are
at first identical, but they are not permanent. The changes that have
always gone on still go on. Some species slowly die out, new ones take
their place, and thus in time the animals and plants of the island come
to differ from those of the country from which it was severed; and if
the subsidence which first separated them goes on widening and deepening
the sea between them, there will come in time to be such a marked difference
in their productions as we see between Madagascar and Africa.

This general principle is of almost universal application,
so that when we find an island whose animals and plants exactly agree
with those of an adjacent land, we look for evidence of its recent separation
from that land; while, on the other hand, any remarkable diversity of
natural productions forces on us the conclusion that the watery barrier
which now exists has existed for a very long geological period; and
when the diversity is almost total, not only in species but in larger
groups such as general families and orders, we conclude that these countries
could never have been connected since our continents and oceans had
assumed their present general outlines.

Returning now to the Malay Archipelago, we see
that
the whole of the seas connecting Java, Sumatra, and Borneo with Malacca
and Siam are under 50 fathoms deep, so that an elevation of only 300
feet would add this immense district to the Asiatic continent. The
100
fathom line will also include the Philippine Islands and the island
of Bali, east of Java. From this we should naturally conclude that
the
subsidence breaking up this portion of Asia had recently taken place,
and we have a very sufficient cause for such subsidence in the vast
range of volcanoes in Sumatra and Java, whose elevatory action must
have been counterbalanced by some [[p. 228]]
adjacent depression. On examining the zoology of these countries this
opinion is confirmed, for we find the most overwhelming evidence that
these great islands must have once formed a part of the continent,
and
could only have been separated at a very recent geological epoch. The
elephant and tapir of Sumatra and Borneo, the rhinoceros of Sumatra
and the allied species of Java, the wild cattle of Borneo and the kind
long supposed to be peculiar to Java, are now known all to inhabit
some
part or other of Southern Asia. None of these large animals could possibly
have passed over the arms of the sea which now separate these countries,
and therefore plainly indicate that a land communication must have
existed
since the origin of the species. Among the smaller mammals a considerable
portion are common to each island and the continent; but the vast physical
changes that must have occurred during the breaking up and subsidence
of such extensive regions have led to the extinction of some in one
or more of the islands, and in some cases there seems also to have
been
time for a change of species to have taken place. Birds and insects
illustrate the same view, for every family and almost every genus of
birds and insects found in any of the islands occur also in the Asiatic
continent, and in a great number of cases the species are exactly identical.
Birds offer us one of the best means of determining the laws of distribution;
for though at first sight it would appear that the watery boundaries
which keep out the land quadrupeds could be easily passed over by birds,
yet practically it is not so, for if we leave out the aquatic tribes
which are pre-eminently wanderers, it is found that the others (and
especially the passeres or true perching-birds which form the vast
majority)
are generally as strictly limited by straits and arms of the sea as
are quadrupeds themselves. As an instance among the islands of which
I am now speaking, it is a remarkable fact that Java possesses numerous
birds which never pass over to Sumatra, though they are separated by
a strait only 15 miles wide, and with islands in mid-channel. Java,
in fact, possesses more birds and insects peculiar to itself than either
Sumatra or Borneo, and this would indicate that it was earliest separated
from the continent; next in organic individuality is Borneo, while
Sumatra
is so nearly identical with the peninsula of Malacca in all its animal
forms, that we may safely conclude it to have been the most recently
dismembered island.

The general result, therefore, at which we arrive
is, that the great islands of Java, Sumatra, and Borneo resemble in
their natural productions the adjacent parts of the continent, almost
as much as such widely-separated districts could be expected to do even
if they still formed a part of Asia; and this close resemblance, joined
with the fact of the wide extent of sea which separates them being so
uniformly and remarkably shallow, and lastly, the existence of the [[p.
229]] extensive range of volcanoes in Sumatra and Java, which
have poured out vast quantities of subterranean matter and have built
up extensive plateaux and lofty mountain ranges, thus furnishing a "vera
causa" for a parallel line of subsidence--all lead us irresistibly
to the conclusion that at a very recent geological epoch the continent
of Asia extended far beyond its present limits in a south-easterly direction,
including the islands of Java, Sumatra, and Borneo, and probably reaching
as far as the present 100 fathom line of soundings.

The Philippine Islands agree in many respects with
Asia and the other islands, but present some anomalies, which seem to
indicate that they were separated at an earlier period, and have since
been subject to many revolutions in their physical geography.

Turning our attention now to the remaining portion
of the Archipelago, we shall find that all the islands from Celebes
and Lombock eastward, exhibit almost as close a resemblance to Australia
and New Guinea as the Western Islands do to Asia. It is well known that
the natural productions of Australia differ from those of Asia more
than those of any of the four ancient quarters of the world do from
each other. Australia, in fact, stands alone: it possesses no apes or
monkeys, no cats or tigers, wolves, bears, or hyenas; no deer, or sheep,
or oxen; no elephant, horse, squirrel, or rabbit; none, in short, of
those familiar types of quadruped which are met with in every other
part of the world. Instead of these, it has marsupials only, kangaroos
and opossums, wombats and the duck-billed platypus. In birds
it is almost as peculiar. It has no woodpeckers and no pheasants, families
which exist in every other part of the world; but instead of them it
has the mound-making brush-turkeys, the honey-suckers, the cockatoos,
and the brush-tongued lories, which are found nowhere else upon the
globe.

[[p. 230]]

Now all these peculiarities exist also in the Australian
portion of the Malay Archipelago, as may be seen by the tables of characteristic
mammals and birds of the two regions. The contrast is nowhere so abruptly
exhibited as on passing from the island of Bali to that of Lombock,
where the two regions are in closest proximity. In Bali we have barbets,
fruit-thrushes, and woodpeckers; on passing over to Lombock these are
seen no more, but we have abundance of cockatoos, honeysuckers, and
brush-turkeys, which are equally unknown in Bali and every island further
west. The strait here is 15 miles wide, so that we may pass in two hours
from one great division of the earth to another, differing as essentially
in their animal life as Europe does from America. If we travel from
Java or Borneo, to Celebes or the Moluccas, the difference is still
more striking. In the first, the forests abound in [[p.
231]] monkeys of many kinds, wild cats, deer, civets, and otters,
and numerous varieties of squirrels are constantly met with. In the
latter none of these occur; but the prehensile-tailed opossum is almost
the only terrestrial animal seen, except wild pigs, which are found
in all the islands, and deer (which have probably been recently introduced)
in Celebes and the Moluccas. The birds which are most abundant in the
Western Islands are woodpeckers, barbets, trogons, fruit-thrushes, and
leaf-thrushes: they are seen daily, and form the great ornithological
features of the country. In the Eastern Islands these are absolutely
unknown, honeysuckers and small lories being the most common birds;
so that the naturalist feels himself in a new world, and can hardly
realise that he has passed from the one region to the other in a few
days, without ever being out of sight of land.

The inference that we must draw from these facts
is undoubtedly that the whole of the islands eastwards from Java and
Borneo do essentially form a part of a former Australian or Pacific
Continent, from which they were separated, not only before the Western
Islands were separated from Asia, but probably before the extreme south-eastern
portion of Asia was raised above the waters of the ocean; for a great
part of the land of Borneo and Java is known to be geologically of quite
recent formation, while the very great difference of species and in
many cases of genera also between the productions of the Eastern Malay
Islands and Australia, as well as the great depth of the sea now separating
them, point to a comparatively long isolation and an early epoch of
separation. It is interesting to observe among the islands themselves
how a shallow sea always intimates a recent land-connection. The Aru
Islands, Mysol, and Waigiou, as well as Jobie, agree with New Guinea
in their mammalia and birds much more closely than they do with the
Moluccas, and we find that they are all united to New Guinea by a shallow
sea. In fact, the 100 fathom line round New Guinea marks out accurately
the range of the true Paradise birds.

The existence of a Pacific continent was long ago
indicated by Mr. Darwin's researches on the structure and origin of
coral-reefs, the numerous atolls and barrier-reefs in the whole of this
district being shown to depend upon the subsidence of land for long
periods. This so exactly agrees with the singular unity now existing
among the organic productions of a vast number of islands, which at
the same time are very different from those of any other part of the
world, that we must accept it as a fair deduction from the only evidence
we can ever hope to obtain of this class of changes.

I would particularly call attention to the fact
that the division of the Archipelago here pointed out, into two regions
characterised by a striking diversity in their natural productions,
does not correspond to any of the physical or climatal divisions
of the surface. [[p. 232]] The great volcanic
chain runs through both parts: Borneo closely resembles New Guinea,
not only in its vast size but in its climate and the general aspect
of its vegetation; the Moluccas are the counterpart of the Philippines
in their volcanic origin, their extreme fertility, their luxuriant forests,
and their frequent earthquakes; and the east end of Java has a climate
almost as dry as that of Timor. Yet between these corresponding groups
of islands, constructed as it were after the same pattern, there is
the greatest possible contrast in the animal productions. Nowhere does
the ancient doctrine--that the peculiar animal and vegetable productions
of the various countries of the globe are directly dependent on the
physical conditions of those countries (such as climate, soil, elevation,
&c.)--meet with a more direct and palpable contradiction. Borneo
and New Guinea, as physically alike as two distinct countries can be,
are zoologically wide as the poles asunder; while Australia, with its
dry winds, its open plains, stony deserts, and temperate climate, yet
produces the quadrupeds and birds which are most nearly allied to those
inhabiting the hot, damp forests which everywhere clothe the plains
and mountains of New Guinea.

We can now give the reason for limiting the Malay
Archipelago on the east by the Solomon Islands in the Pacific Ocean.
Certain groups of birds, which have their metropolis in New Guinea
and
extend over the Moluccas to the westward, are found also as far as
the
Solomon Islands to the eastward, but do not extend to New Caledonia
(which is much more Australian in its productions), or to the Fejee
Islands, where the peculiar Pacific fauna commences. These groups are
the scarlet lories and the white cockatoos, and the occurrence
of a new species of cassowary in New Britain is a further indication
of these islands being as closely allied to New Guinea on the one hand
as are the Moluccas on the other.

The nature of the contrast between these two great
divisions of the Malay Archipelago will be best understood by considering
what would take place if any two of the primary divisions of the earth
were brought into equally close contact. Africa and South America, for
example, differ very greatly in all their animal forms. On the one side
we have baboons, lions, elephants, buffaloes, and giraffes; on the other
spider-monkeys, pumas, tapirs, ant-eaters, and sloths; while among birds,
the hornbills, turacos, orioles, and honey-suckers of Africa contrast
strongly with the toucans, macaws, chatterers, and humming-birds of
America.

But let us endeavour to imagine (what it is very
probable may occur in future ages) that a slow upheaval of the bed
of
the Atlantic should take place, while at the same time earthquake-shocks
and volcanic action on the land should cause increased volumes of sediment
to be poured down by the rivers, so that the two continents should
gradually
spread out by the addition of [[p. 233]]
newly-formed lands, so as to reduce the Atlantic which now separates
them to an arm of the sea a few hundred miles wide. At the same time
we may suppose islands to be upheaved in mid-channel, and, as the subterranean
forces varied in intensity and shifted their points of greatest action,
these islands would sometimes become connected with the land on one
side or other of the strait, and at other times again be separated
from
it. Several islands would at one time be joined together, at another
would be broken up again, till at last, after many long ages of such
intermittent action, we might have an irregular archipelago of islands
filling up the ocean channel of the Atlantic, in whose appearance and
arrangement we could discover nothing to tell us which had been connected
with Africa and which with America. The animals and plants inhabiting
these islands would, however, certainly reveal this portion of their
former history. On those islands which had ever formed a part of the
South American continent we should be sure to find such common birds
as chatterers and toucans and humming-birds, and some of the peculiar
American quadrupeds; while on those which had been separated from Africa,
hornbills, orioles, and honey-suckers would as certainly be found.
Some
portion of the upraised land might at different times have had a temporary
connection with both continents, and would then contain a certain amount
of mixture in its living inhabitants. Such seems to have been the case
with the islands of Celebes and the Philippines. Other islands, again,
though in such close proximity as Bali and Lombock, might each exhibit
an
almost unmixed sample of the productions of the continents of which
they had directly or indirectly once formed a part.

In the Malayan Archipelago we have, I believe, a
case exactly parallel to that which I have here supposed. We have indications
of a vast continent, with a peculiar fauna and flora, having been gradually
and irregularly broken up; the island of Celebes probably marking its
furthest westward extension, beyond which was a wide ocean. At the same
time Asia appears to have been extending its limits in a south-east
direction, first in an unbroken mass, then separated into islands as
we now see it, and almost coming into actual contact with the scattered
fragments of the great southern land.

In dwelling upon this subject--which I trust I have
succeeded in making intelligible--my object has been to show the important
bearing of researches into the natural history of every part of the
world upon the study of its past history. An accurate knowledge of any
group of birds or of insects, and of their geographical distribution,
may assist us to map out the islands and continents of a former epoch;
the amount of difference that exists between the [[p.
234]] animals of adjacent districts being closely dependent upon
preceding geological changes. By the collection of such minute facts
alone can we hope to fill up a great gap in the past history of the
earth as revealed by geology, and obtain some indications of the existence
of those ancient lands which now lie buried beneath the ocean, and have
left us nothing but these living records of their former existence.

It is for such inquiries the modern naturalist
collects
his materials; it is for this that he still wants to add to the apparently
boundless treasures of our national museums, and will never rest satisfied
as long as the native country, the geographical distribution, and the
amount of variation of any living thing remains imperfectly known.
He
looks upon every species of animal and plant now living as the individual
letters which go to make up one of the volumes of our earth's history;
and, as a few lost letters may make a sentence unintelligible, so the
extinction of the numerous forms of life which the progress of cultivation
invariably entails will necessarily render obscure this invaluable
record of
the past. It is, therefore, an important object, which governments
and
scientific institutions should immediately take steps to secure, that
in all tropical countries colonised by Europeans the most perfect collections
possible in every branch of natural history should be made and deposited
in national museums, where they may be available for study and interpretation.

If this is not done, future ages
will certainly look back upon us as a people so immersed in the pursuit
of wealth as to be blind to higher considerations. They will charge
us with having culpably allowed the destruction of some of those records
of Creation which we had it in our power to preserve; and while professing
to regard every living thing as the direct handiwork and best evidence
of a Creator, yet, with a strange inconsistency, seeing many of them
perish irrecoverably from the face of the earth, uncared for and unknown.

* * *

[[p. 210]] The
PRESIDENT remarked that as a geologist, he must say, in all the years
he had had the
honour of being connected with the Society, he had never heard a paper read of
a more luminous character,
and which so bound together in the most perfect forms all the branches of the
science of natural history,
more particularly as it developed the truths of geography upon what he considered
to be its soundest basis,
that of geological observation and analogy. He was perfectly certain there was
no person present, who
could not say that they had never sent a traveller into a foreign country, who
had more completely studied
all the grand features of its natural history, or who had combined them together
in a more profoundly
philosophical spirit.

Mr. CRAWFURD said the subject of the Malay Archipelago
had been the study of his life; but he felt
himself much enlightened by the paper of Mr. Wallace. He did not know that he
could add any
information. He might not entirely agree with all his theories, and, perhaps,
not even with his divisions of
the Archipelago; but for all that, his paper was a most enlightened [[p.
211]] and a most able one. He
wished Mr. Wallace had said something about the human inhabitants of these regions.
Mr. Wallace knew
more about them than any Englishman, for he had lived among them; and he should
be glad to hear his
opinion of them. He divided the Archipelago into two parts, the Indian portion
and the Australian portion.
Now he wished to ask Mr. Wallace, seeing that he conjoined Australia and
New Guinea as part of the
same region, how it happened that the human inhabitants were totally different?
Again, if the Indo-Malay
portion of the Islands were grouped with India, how came it that no two human
beings could be more
unlike than the Hindoo and the Malay? How did the Malays come there? How were
the dwarfish
inhabitants of the Andaman Islands to be accounted for? for there were no such
people in India--that was
certain. How were the pigmy negroes of the Malay Peninsula to be accounted for?
There were differences
here which he (Mr. Wallace) might perhaps be able to reconcile. Mr. Wallace had
mentioned the eruption
of the mountain Tomboro. He was himself old enough to have been an eye-witness
of the commencement
of that eruption, probably the most remarkable one on record. In the year 1814
he proceeded with an
expedition to the island of Celebes; and as they approached the island of Sumbawa,
which contained this
famous mountain, they thought they saw a very heavy squall coming on. They were
beating up against the
south-east monsoon, and as they approached they saw that it was a volcano. As
they beat up nearer the
shore of the island, the ashes fell on the deck. That was one whole year before
the great eruption took
place. He was then at Soerabaya, at the eastern extremity of Java, about 300
miles distant from the
mountain of Tomboro. For three days it was pitch dark. Mr. Wallace had greatly
underrated the extent of
ashes that were ejected, which were certainly not confined to an area of 300
miles, as they fell at
Bencoolen, 1200 miles distant, transported thither by the south-east monsoon;
and they were carried by a
second current of air a thousand miles in an opposite direction, as far, in fact,
as the island of Banda. For
ten days he had to write by candlelight; and the country-people were compelled
to travel into the country
with flambeaux. For six weeks together they could not see the plain disc of the
sun. There was one
difference between the volcanic and non-volcanic portions of these islands. Generally
speaking, the
volcanic part was highly fertile. Mr. Wallace had given a just eulogy of the
island of Java. He himself
resided on that island six years, and he was tolerably well acquainted with it.
Java was about half the size
of Great Britain; it was a fertile island, beautifully watered, and at present
contained a population of full
12,000,000; indeed, the last accounts make it about 13,200,000. On the other
hand, he did not believe the
population of Borneo exceeded four or five inhabitants to the square mile, and
probably on the whole did
not exceed one million and a quarter. If Borneo were as fertile as Java, as well
watered, and as suitable to
maintain a population, it ought, according to its immense size, to contain a
population of 80,000,000. The
people of Java were civilised, having fine monuments and a literature. The whole
of the inhabitants of
Borneo, who were not strangers, were savages. There was a still more remarkable
example. Mr. Wallace
had mentioned the islands of Bali and Lombok. Now, those two very small islands
were highly fertile, and
although they were not above one-eightieth part of the size of Borneo, they contained
a population equal to
that of Borneo, and a civilised population too, well-clothed and well-fed, and
possessing a literature. These
were striking differences between the volcanic and non-volcanic islands.

Mr. WALLACE said with regard to the question that Mr. Crawfurd had asked, why
he did not refer to
the races of men inhabiting these islands, it was simply because his paper was
already too long, and it
would require another paper equally long to do justice to the subject.

Mr. CRAWFURD.--Will you promise one?

Mr. WALLACE.--Certainly. He should just like to say a word with regard [[p.
212]] to the number of
very difficult problems that Mr. Crawfurd had proposed to him--problems
which, as Mr. Crawfurd, who
had devoted his whole life to the subject, was unable to answer, it was not likely
he should be able to
answer upon such short notice, if indeed at all. However, he would say, generally,
that the races of man do
not correspond at all accurately to those two great divisions of the Archipelago,
which differed so
remarkably in their natural productions. The reason why they did not correspond
appeared to him to be
simply this; that man is a migratory animal and continually moving about. We
had a great deal of historical
evidence of the number of changes of the races of man in the Archipelago itself.
Some races have been
driven out; others have come in; others have made conquests; others have gone
to more fertile regions.
Therefore, the races of man would not correspond to those of animals and plants.
Still there was a slight
general correspondence. There was the Malay race, the whole of which, generally
speaking, corresponded
to the western half of the Archipelago; they did stretch into the eastern half,
but not a great part of it. The
Papuan race occupied the eastern half, and extended into New Guinea. It was probable
they had extended
still further west, but they had been driven back by the Malayan race.

The PRESIDENT, in adjourning the Meeting, congratulated them upon having had
from Mr. Wallace
a proof that Geography as a science embraced all the sciences relating to Natural
History. He had proved
himself not alone a first-rate naturalist, but also a good geologist.

The Meeting then adjourned, after a cordial vote of thanks had been unanimously
passed to Mr.
Wallace for his most interesting and instructive paper.

*
*
*
*
*

Comment by Bernard Michaux, paleobiologist (pers. commun. 7/00):

With some wonderful turn of phrase Wallace's paper
gave most British and European readers their first summary description
of the natural circumstances of the Malay Archipelago. In 1863 there
wasn't even a map that showed the region in its entirety. Wallace
notes that "this sea of islands" is in fact continental in extent
(some 10 million square miles), and his evocative description of Borneo's
size, in which "the whole of Great Britain and Ireland, with all their
islets from Scilly to Shetland" would easily fit "and still leave
boundless forests stretching out like an ocean beyond them," is wonderful
writing. What Wallace wants to do is to convince his readers that
Indonesia is deserving of being considered its own major biogeographic
region.

Wallace's style of writing here is part scientific,
part travelogue. He compares and contrasts the physical geography,
climate and vegetation over this broad region before getting down
to the real business of biogeographical interpretation. Wallace's
Line is clearly described, and the relationship between the distribution
of Australian and Asian mammals and birds discussed in the light of
what Wallace knew of Indonesian geology. This latter discussion is
now of historical interest only, unlike his biological observations,
which largely retain their relevance to modern readers. It is a sad
fact that the Indonesia Wallace knew is rapidly disappearing, making
the conservation of Indonesia's remaining biodiversity an ever more
pressing problem. It would be a wonderful memorial to Wallace if the
biological diversity he so ably promoted to the Victorians survived,
in some sustainable way, in perpetuity.